Windows can be disposed in the wall of a substrate process chamber to allow radiant energy from a light source to enter the processing volume of the process chamber. In some applications, windows may be utilized in systems configured for epitaxial deposition at reduced pressures (e.g., below atmospheric pressure). Unfortunately, the inventor has discovered that conventional windows, such as a flat, single piece of quartz or the like, perform poorly where large pressure differentials exist between the interior and exterior of the processing volume (e.g., between atmospheric pressure outside of the process chamber and the reduced pressure within the process chamber). The inventors have further discovered that conventional windows can be a source of heat loss from the processing volume and fail to provide any means for tuning the temperature of the window or the direction and/or intensity of the radiant energy entering the processing volume.
Accordingly, the inventor has provided an improved window assembly.